Self tuning adaptive bucket memory manager

ABSTRACT

Disclosed herein are system, method, and computer program product embodiments for adaptively self-tuning a bucket memory manager. An embodiment operates by receiving requests for memory blocks of varying memory sizes from a client. Determining a workload for the client based on the requests. Analyzing buckets in the bucket memory manager based on the workload. Adjusting parameters associated with the bucket memory manager based on the analyzing to accommodate the requests.

BACKGROUND

Generally, in a typical computing environment, a memory managerallocates memory for various applications. The applications may requestmemory of varying sizes, from small chunks of memory to large chunks ofmemory. In return, the memory manager allocates the requested size froma block of memory and distributes the allocated memory to theapplication. However, there may be issues with performance inefficiently distributing memory of varying sizes. Specifically, memorymanagers tend to degrade the longer they run because as they allocatefrom the block of memory, the block of memory becomes fragmented. As aresult, the memory manager may take a longer time to scan the fragmentedblock of memory to find a requested memory size.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated herein and form a part of thespecification.

FIG. 1 is a block diagram of a distributed database system including aplurality of nodes each with a bucket memory manager, according to someembodiments.

FIG. 2 is a block diagram of a bucket memory manager, according to someembodiments.

FIG. 3 is a block diagram of an engine interacting with a bucket in abucket memory manager, according to some embodiments.

FIG. 4 is a block diagram of a fragmented memory block, according tosome embodiments.

FIG. 5 is a flowchart illustrating operations of the bucket memorymanager, according to some embodiments.

FIG. 6 is a flowchart illustrating a self-tuning mechanism in a bucketmemory manager, according to some embodiments.

FIG. 7 is a flowchart illustrating operations of a self-tuning mechanismin a bucket memory manager, according to some embodiments.

FIG. 8 is a block diagram of a self-tuning environment, according tosome embodiments.

FIG. 9 is an example computer system useful for implementing variousembodiments or portions thereof.

In the drawings, like reference numbers generally indicate identical orsimilar elements. Additionally, generally, the left-most digit(s) of areference number identifies the drawing in which the reference numberfirst appears.

DETAILED DESCRIPTION

Provided herein are system, apparatus, device, method and/or computerprogram product embodiments, and/or combinations and sub-combinationsthereof, for adaptively self-tuning a bucket memory manager.

FIG. 1 is a block diagram 100 of a client 102 interfacing with adatabase management system (DBMS) 104, according to an embodiment. TheDBMS 104 may include a database 106 having a plurality of nodes 108. Thenodes 108 of database 106 may be distributed within one or more machinesor computers, over local or diverse geographic areas.

Nodes 108 may each include one or more processors, bucket memory manager110, local memory 112, and a connection to one or more other nodes 108of database 106. Local memory 112 may be directly accessible via ahigh-speed bus or other connection 120. Additionally, the nodes 108 mayaccess the memory 112 of one or more other nodes 108 through one or moreinterconnects 120.

An interconnect may be a connection or communication pathway between twoor more nodes 108, enabling the nodes to communicate with one anotherincluding accessing the memories 112 of other nodes 108. For example,Node 108-0 may have access to both local memory 112-0, as well as remotememory 112-1. Memory 112-1 may be considered local memory to Node 108-1,and remote memory to any other nodes 108 accessing memory 112-1,including Node 108-0. For example, remote memory 112-0 may be any memorythat is accessible via a connection through one or more additional nodes108-1, 108-2, and 108-3 other than the local node 108-0.

In an embodiment, the bucket memory manager 110, in any given node 108,may interact with other bucket memory managers 110 in other node 108through the interconnect 120. In addition, as noted above, each bucketmemory manager 110 has access to the respective local memory 112 of itsown node 108 and any of the other remote memories 112 of other nodes108. For example, bucket memory manager 110-0 may have access to bucketmemory manager 110-3 and remote memory 112-3.

In an embodiment, DBMS 104 may receive a request from a client 102 fordata 114. DBMS 104 may determine that data 114 does not exist within thedatabase 106 (e.g., in the memory 112 of any of the nodes 108). DBMS 104may then need to load data 114 from a disk 116 into one or more memories112. Alternatively, for example, client 102 may request that data 114 beloaded into database 106 from disk 116.

Disk 116 may be a tape drive, hard drive disk, or other storage(generally referred to as secondary storage) that requires greaterresources (including, but not limited to time) by which to perform dataaccess. For example, generally, data stored in memory 112 may beaccessed more quickly than data 114 when stored in disk 116.

FIG. 2 is a block diagram of a bucket memory manager 110, according toan embodiment. As mentioned above, each of the nodes 108 include bucketmemory manager 110. The bucket memory manager 110 interacts with thememory 112 and processes requests from clients 102 for memory blocks ofparticular sizes.

In an embodiment, the bucket memory manager 110 may include one or morefixed size buckets 202, one or more global buckets 204, one or moreinstances 206, and one or more associated engines 208. A bucket 202, 204is a container for storing pointers to memory blocks in each of thememories 112. The fixed size buckets 202 each store pointers to memoryblocks of a particular size. For example, fixed size bucket 202-1 maystore pointers to one or more 1-megabyte (MB) allocations from memory112-0 in node 108-0. In another example, bucket 202-2 may storeaddresses for one or more 3 MB allocation from memory 112. Each of thefixed size buckets 202-1 through 202-N are associated with memory blocksof a particular size.

In an embodiment, the global bucket 204 stores pointers to memory blocksof sizes not stored by fixed size buckets 202. For example, fixed sizebucket 202-1 may store a plurality of 1 MB memory sizes, fixed sizebucket 202-2 may store a plurality of 3 MB memory sizes, fixed sizebucket 202-3 may store a plurality of 5 MB memory sizes, whereas globalbucket 204-1 may store memory blocks of other memory sizes from memory112. Thus, global bucket 204-1 is used to process memory requests ofmemory blocks not associated with the fixed size buckets 202.

Each instance 206 comprises an engine 208, one or more fixed sizebuckets 202, and a global bucket 204, according to an embodiment. Forexample, instance 206-1 comprises engine 208-1, fixed size buckets 202-1through 202-N, and global bucket 204-1.

In an embodiment, the bucket sizes associated with the fixed sizebuckets 202 for the instances 206 are the same. The number of buckets202, 204 in each of the instances 206 is the same. For example, eachinstance 206 has one global bucket 204, one engine 208 and N number offixed sizes buckets 202. The fixed size buckets 202 across each of theinstances 206 store pointers to memory blocks of the same size. Forexample, fixed size bucket 202-1 in each of the instances 206 may storepointers to memory blocks of 1 MB; fixed size bucket 202-2 in each ofthe instances 206 may store pointers to memory blocks of 3 MB; and,fixed size bucket 202-3 in each instance 206 may store pointers tomemory blocks of 5 MB. In an alternative embodiment, the fixed sizebuckets 202 across each of the instances 206 store pointers to memoryblocks of different sizes.

In an embodiment, the pointers in each of the fixed size buckets 202,204 across each of the instances point to different memory blocks. Forexample, each of the buckets 202, 204 stores data structures 210containing the pointers to the memory blocks of a particular size. Thedata structures 210 will be explained further below.

In an embodiment, engine 208 is a transaction manager for each of thebuckets 202, 204. The engine 208 manages communication between theclient 102, the fixed size buckets 202, the global bucket 204, and thememory 112 for its respective instance 206. For example, engine 208-1may access and retrieve the pointers to a memory block of a particularsize from fixed size bucket 202-1 based on a request from client 102.Then, the engine 208-1 may access and retrieve the block of memory inmemory 112 pointed to by the retrieved pointer.

In an embodiment, the engine 208 may access and insert fragments intothe data structures 210 of the buckets 202, 204. The engine 208 may lockaccess to the accessed bucket 202, 204 so no other engines 208 haveaccess to that bucket. For example, engine 208-1 may access globalbucket 204-1 in instance 206-1 to retrieve a memory address notassociated with a fixed size bucket 202. The engine 208-1 may use aspinlock on global bucket 204-1 so the other engines 208-2 through 208-Ncannot access the contents of global bucket 204-1 in instance 206-1while engine 208-1 accesses global bucket 204-1. However, the spinlockmay only apply to a particular bucket of a particular instance, such asglobal bucket 204-1 in instance 206-1. Engine 208-2 may therefore accessany other bucket in instance 206-1 other than the global bucket 204-1during the time engine 208-1 accesses the global bucket 204-1.

In an embodiment, as noted above, each engine 208 is associated with aninstance 206. For example, engine 208-1 is associated with instance206-1. Engine 208-1 initially accesses and retrieves buckets from fixedsize buckets 202 or global buckets 204 in instance 206-1. If engine208-1 does not find a requested memory size in instance 206-1, engine208-1 may access the fixed size buckets 202 or global buckets 204 in theother instances 206-2 through 206-N. For example, engine 208-1 mayretrieve a pointer to a 1 MB memory allocation from fixed size bucket202-1 from associated instance 206-1. However, in the case that thefixed size bucket 202-1 is empty and does not have any pointers to a 1MB memory allocations, engine 208-1 will search for a pointer to a 1 MBmemory allocation in the next available instance 206. Engine 208-1 willthen check the fixed size bucket 202-1 in instance 206-2. The engine208-1 will continue to check each other instance 206 until a pointer toa 1 MB memory allocation is retrieved. As mentioned above, uponretrieval the engine 208-1 carves the memory block from memory 112 basedon the pointer and passes the memory block to client 102.

In an embodiment, a processor associated with each of the nodes 108 mayrandomly assign an engine 208 to one of the instances 206 associatedwith that node 108 based on a thread id number or a random seed idnumber. For example, processor of node 108-0 assigns id number 4 toengine 208-1 of node 108-0. Id number 4 associates engine 208-1 toinstance 206-4 of node 108-0. By associating an id number to each engine208 in a respective node 108, each engine 208 is guaranteed to beassociated with a different instance 206 upon boot up.

In an embodiment, engine 208 may access memory 112 after recognizing oneor more of the buckets are empty across all the instances 206. Forexample, engine 208-1 recognizes fixed size bucket 202-1 and globalbucket 204 in each instance 206 is empty when accessing and trying toretrieve a pointer to a 1 MB memory allocation. In response, engine208-1 in node 108-0 will initially search in memory 112-0 in node 108-0and scan for a memory chunk size of 1 MB. If local memory 112-0 providesno size of a contiguous 1 MB memory address space, then engine 208-1will search in memory 112-1. The engine 208-1 scans each subsequentmemory 112 for a 1 MB memory allocation until one is found. Upon findinga 1 MB allocation in a memory 112, engine 208-1 allocates the 1 MB blockof memory from the memory 112 and stores a pointer to the address infixed size bucket 202-1.

In an embodiment, engine 208 returns the memory block from client 102 tothe memory 112. For example, engine 208 deallocates the memory blockback to memory 112. In addition, the engine 208 returns the pointer tothe memory block to the bucket where the pointer was originallyretrieved. For example, engine 208-1 accesses fixed size bucket 202-1for retrieving a pointer to a 1 MB memory allocation for client 102.Engine 208-1 passes the 1 MB memory allocation to client 102 based onthe pointer. After client 102 finishes using the 1 MB memory, client 102releases and deallocates the 1 MB memory address back to node 108. Theengine 208-1 also returns the pointer to the deallocates 1 MB memoryallocation to fixed size bucket 202-1.

In an embodiment, engines 208 may simultaneously be able to handlemultiple tasks. These task may be searching for and allocating memoryfrom memory 112; processing requests from client 102; and, interactingwith the different buckets. In an alternative embodiment, an engine 208which is not active may be used to scan the buckets in each of theinstances 206 and fill the buckets with pointers to memory addresses toa max fill threshold. For example, engine 208-3 is not active.Specifically, engine 208-3 has not received a request from client 102.Accordingly, engine 208-3 may scan each bucket 202, 204 in each of theinstances 206 to examine the max fill level of each bucket 202, 204. Ifengine 208-3 recognizes fixed size bucket 202-1 has 5 pointers and themax fill threshold is 10 pointers, engine 208-3 may scan the associatedmemory 112, such as memory 112-0, and allocate 5 more pointers to memoryblocks for fixed size bucket 202-1 to meet the max fill threshold.

In an embodiment, the max fill threshold may be predefined by aconfiguration file. The configuration file may be read by every engine208 upon boot up of the DBMS 104. For example, the configuration filemay specify a max fill threshold of 10 memory addresses for each bucket.The max fill threshold may be chosen based on the size of the memoryallocated for the bucket memory manager 110. The memory allocated forthe bucket memory manager 110 will be explained below.

FIG. 3 is a block diagram of an engine 208-1 interacting with a fixedsize bucket 202-1 in the bucket memory manager 110, according to anembodiment. The engine 208-1 communicates with interface 302 of fixedsize bucket 202-1. The interface 302 allows the engine 208-1 tocommunicate with the data structures 210. Specifically, engine 208-1communicates with the interface 302 to retrieve particular memoryaddresses from the data structures 210. Further, the engine 208-1communicates with the interface 302 to insert new memory addresses intothe data structure 210. In addition, the engine 208-1 may communicate tothe interface 302 to remove all the data structures 210.

In an embodiment, each of the buckets 202, 204 adheres to thearchitecture described in FIG. 3. For example, each of the buckets 202,204 includes data structures 210 containing one or more data elements304. Each data element 304 contains a memory address, a size associatedwith the memory address, and a pointer, such as pointers 306 through316, pointing to the address of the next data element 304.

In an embodiment, the data structures 210 organize the data elements 304in a manner that facilitates easy retrieval and insertion. For example,the data elements 304 shown in FIG. 3 are organized in a linked listmanner. The linked list manner includes a data element 304 and a pointer306 pointing to the next data element 304. The last data element 304-6includes a pointer 316 pointing to NULL. The NULL denotes the end of thelinked list. The data structures 210 may not be limited to linked listsbut may also be organized as dynamic arrays, stacks, queues, hashtables, heaps, and binary trees, according to some embodiments.

FIG. 4 is a block diagram of a memory block 112, according to anembodiment. The memory block 112 shows the various memory locations 402through 412 pointed to by pointers 306 through 316 respectively. Asshown in FIG. 3, the pointers 306 through 316 are contained by the fixedsize bucket 202-N from the data elements 304 in FIG. 3. Also mentionedabove, the data elements 304 contain only the addresses, the pointers tothe addresses, and size of the memory location, not the memory itselffrom memory block 112. In addition, bucket memory manager 110 iscontained in memory 112. A chunk of memory from memory 112 is set asideto store the contents of the bucket memory manager 110. This chunk ofmemory for the bucket memory manager 110 is calculated upon the max fillthreshold of each data structure, the number of instances 206 allocated,and the number of buckets within those instances 206 upon boot up,according to an embodiment. The max fill threshold, the number ofinstances 206, and the number of buckets within those instances 206 maybe preconfigured in the configuration file to be read upon boot up ofthe DBMS 104.

FIG. 5 is a flowchart for a method 500 for operations of the bucketmemory manager 110, according to an embodiment. Method 500 can beperformed by processing logic that can comprise hardware (e.g.,circuitry, dedicated logic, programmable logic, microcode, etc.),software (e.g., instructions executing on a processing device), or acombination thereof.

In 502, an engine 208 retrieves configuration information from aconfiguration file for the bucket memory manager parameters. Forexample, upon boot up of the DBMS 104, engines 208 in each of the nodes108 read information from a configuration file. Specifically, theinformation may consist of the number of instances 206 for each bucketmemory manager 110, the number of buckets 202, 204 for each instance206, the bucket sizes for the fixed size buckets 202, and a max fillthreshold for each of the buckets 202, 204. In addition, theconfiguration information may contain a bucket memory manager run mode.Specifically, the bucket memory manager run mode may operate in twodifferent settings. The two settings are manual mode and self-tuningmode. The method 500 illustrates the manual mode where the bucket sizesfor the fixed size buckets 202 are pre-configured based on theinformation read from the configuration file. The self-tuning mode willbe further explained below. In an embodiment, the configuration file maybe stored in disk 116 and configured by a client 102.

In 504, the bucket memory manager parameters are configured based on theconfiguration information retrieved from the configuration file. Forexample, as mentioned above, nodes 108 are initialized based on theconfiguration information to have 5 instances 206; each instance 206contains 4 fixed size buckets 202; and, the bucket sizes of each bucket202, 204 are 1 MB, 3 MB, 5 MB, and 10 MB. In addition, the max fillthreshold for each of the buckets 202, 204 has a fill level of 20.However, these numbers are for illustrative purposes only, other numbersmay be used.

In 506, the database 106 receives a request from client 102 for arequested memory size. For example, client 102 launches a particularapplication, such as a word document, which requires a particular memorysize to execute and run. The database 106 receives a request from client102 for a particular memory size, such as 3 MB, in order to run the worddocument. In an embodiment, a node 108 is chosen to receive the requestof client 102, such as node 112-0, based on a workload of the nodes. Anengine 208, such as engine 208-1 in node 112-0, receives the requestfrom client 102.

In 508, an engine 208, such as engine 208-1, scans the fixed sizebuckets 202-1 through 202-N of an associated instance 206 for aparticular memory size based on a requested memory size from a client102. For example, engine 208-1 receives a 3 MB request from client 102.In response, engine 208-1 scans for a match of a bucket size in thefixed size buckets 202 and the global bucket 204. In an embodiment, theengine 208 scans the fixed size buckets 202 first before scanning theglobal bucket 204.

In 510, engine 208 determines if a match was found in one of the fixedsize buckets 202. For example, engine 208-1 scans for 3 MB sizes in thefixed size buckets 202. Engine 208-1 finds fixed size bucket 202-3 holdspointers to 3 MB memory blocks. In 514, that memory pointer is retrievedfrom the data structure 210 in the associated fixed size bucket 202,such as fixed size bucket 202-3. In response, the engine 208 grabs theallocated memory block based on the memory pointer.

If a match was not found, then in 512, the engine 208 scans the globalbucket 204 for the requested memory size. In an embodiment, the globalbucket 204 stores the pointers of various memory addresses andassociated sizes in ascending order. In an embodiment, the global bucket204 stores the various addresses and associated sizes in ascending orderof the addresses. The ascending order architecture facilitates theengine 208 to efficiently find a memory address of the requested size.

In 516, the engine 208 passes the requested memory block based on theretrieved pointer to the client 102. For example, the engine 208 passesthe memory block 402 from memory 112 based on the pointer 306 retrievedfrom the fixed size bucket 202-1 to the client 102. In an embodiment,the engine 208 maintains a tracking system to determine which memoryaddresses or memory blocks 402 through 412 are currently in use by aclient 102. This ensures another engine 208 does not allocate a memoryblock overlapping with memory currently in use by the client 102.Specifically, the tracking system may be a table stored in the disk 116storing a copy of the pointers 306 through 316 of the requested memoryblocks. In an alternative embodiment, each bucket memory manager 110keeps track of the memory block addresses in the respective engines 208.

In 518, the engine 208 receives the returned memory block from client102 upon completion or application closing. For example, client 102frees the 3 MB memory address and the engine 208 returns the pointer 306of the 3 MB memory address to the associated fixed size bucket 202-1.Specifically, the engine 208 inserts the returned pointer 306 back intothe data structure 210 in the same fixed size bucket 202-1 from where itwas retrieved. In an embodiment, the engine 208 clears an entry in thetracking system associated with the returned pointer.

FIG. 6 is a flowchart illustrating a self-tuning mechanism in a bucketmemory manager, according to some embodiments. Method 600 can beperformed by processing logic that can comprise hardware (e.g.,circuitry, dedicated logic, programmable logic, microcode, etc.),software (e.g., instructions executing on a processing device), or acombination thereof.

In 602, requests are received for memory blocks of various sizes fromclient 102. In an embodiment, the DBMS 104 may receive requests formemory blocks from client 102 of various sizes such as 3 MB, 4 MB, and 5MB. These various sizes are based on the applications of client 102.

In 604, a workload for client 102 is determined based on the memoryrequests. In an embodiment, the workload of client 102 is based on aplurality of factors of the memory requests. For example, the workloadmay be the types of memory requests, the sizes of memory requests, andthe frequencies of memory requests from a client 102. More detail willbe explained below.

In 606, the existing buckets 202, 204 are analyzed based on a workloadof client 102. In an embodiment, the bucket memory manager 110continuously monitors parameters associated with the buckets 202, 204.The parameters associated with the buckets 202, 204 may be the number ofdata elements 304 or fragments in the buckets 202, 204; the allocationsassociated with an engine; total number of memory requests for eachinstance 206; the total number of buckets 202, 204 and the total numberof instances 206; locking conditions associated with the buckets 202,204; the sizes of the fixed size buckets 202, and, any configurationsetting stored in the configuration file. More detail on each of theseparameters will be explained below.

In 608, parameters associated with the bucket memory manager 110 areadjusted based on the analyzing to accommodate the requests. In anembodiment, the bucket memory manager 110 adjusts the bucket memorymanager parameters based on the set of rules extracted from theconfiguration information. More detail on the adjustment of theseparameters will be explained below.

FIG. 7 is a flowchart for a method 700 for operations of the self-tuningmechanism in the bucket memory manager 110, according to an embodiment.Method 700 can be performed by processing logic that can comprisehardware (e.g., circuitry, dedicated logic, programmable logic,microcode, etc.), software (e.g., instructions executing on a processingdevice), or a combination thereof.

In 702, the engine 208 retrieves configuration information from aconfiguration file for the bucket memory manager parameters. Forexample, upon boot up of the DBMS 104, engines 208 in each of the nodes108 read information from a configuration file. Specifically, theinformation may consist of the number of instances 206 for each bucketmemory manager 110, the number of buckets for each instance 206, thebucket sizes for the fixed size buckets 202, and a max fill thresholdfor each of the buckets. As mentioned above, the configuration file alsoincludes a bucket memory manager run mode. As method 500 aboveillustrates the manual mode of the bucket run manager flag, methods 600above and 700 below illustrates the self-tuning mode where the bucketmemory manager run mode is set to self-tuning mode. Further, theconfiguration information includes a set of rules for the bucket memorymanager 110 to follow while the bucket run manager flag is set to theself-tuning mode. These set of rules instruct the bucket memory manager110 for running in self-tuning mode, as explained below.

In 704, the bucket memory manager parameters are configured based on theself-tuning mode and the configuration information retrieved from theconfiguration file. For example, when in the self-tuning mode, theconfiguration information initially sets the number of instances 206 foreach bucket memory manager 110, the number of buckets for each instance206, and a max fill threshold for each of the buckets. The otherconfiguration information, as mentioned in the above paragraph, adaptsto the needs of client 102, according to an embodiment. In analternative embodiment, in the self-tuning mode, the bucket memorymanager parameters adapt to a particular need of client 102.

In 706, the database 106 receives a request from client 102 for arequested memory size. The same function occurs here as mentioned abovein 506 and 602. In addition, a memory request counter is initialized foreach new memory request made from client 102. For example, a memoryrequest counter for 1 MB is initialized to 1 when a request for 1 MB isreceived. The associated memory request counter is incremented by onefor each subsequent memory request of the same size. In an embodiment,all of the engines 208 maintain and monitor each of the memory requestcounters. In an alternative embodiment, each request from a client 102is stored in an array to track all requests, as explained below.

In 708, the bucket memory manager 110 analyzes a workload of a client102. For example, the workload may be the types of memory requests, thesizes of memory requests, and the frequencies of memory requests from aclient 102. In addition, the bucket memory manager 110 analyzes theamount of time a memory block is utilized by the client 102. In anembodiment, the amount of time a memory block is utilized by client 102initializes when the engine 208 passes the memory block to the client102 and ends when the engine 208 receives the memory block from theclient 102. The engine 208, which passes and receives the memory blockto and from client 102, tracks the time utilized via a timer.

In 710, the bucket memory manager 110 analyzes the supply of buckets.Specifically, the bucket memory manager 110 continuously monitorsparameters associated with the buckets. In an embodiment, the bucketmemory manager 110 monitors the number of times an engine 208 steals amemory address from another instance 206. For example, the engine 208-1accesses fixed size bucket 202-1 in an associated instance 206-1 for a 1MB memory address. However, fixed size bucket 202-1 is empty and doesnot have any 1 MB memory addresses. In response, engine 208-1 may accessfixed size bucket 202-1 in another instance 206-2 and steal a 1 MBmemory allocation to give to client 102. The number of times an engine208 steals a memory address from another instance 206 is stored in avariable labeled instance_empty. The contents of the instance_empty areincremented by one each time this situation occurs.

In an embodiment, the bucket memory manager 110 monitors the number ofdata elements 304 or fragments in each data structure 210. For example,data structures 210 may each contain a different number of data elements304 ranging from 0 to max fill threshold. Each engine 208 continuouslymonitors the data elements 304 in each of the buckets 202, 204 with theassociated instance 206. The number of data elements 304 in a snapshotis stored in variable numfrags. The snapshot may be taken periodically,such as every hour, and before the system shuts down.

In an embodiment, the bucket memory manager 110 monitors parametersassociated with the number of fragments in each fixed size bucket 202and global bucket 204. For example, each engine 208 monitors the rangeof the number of fragments in each of the buckets. Specifically, theengine 208 monitors the highest and the lowest number of fragmentsobtained in each data structure 210. The highest number of fragments isstored in a variable labeled highwatermark and the lowest number offragments is stored in a variable labeled lowwatermark. The contents ofthese two variables are stored from a snapshot at an instance in time ofthe bucket memory manager 110. The snapshot may be taken periodically,such as every hour, and before the system shuts down.

In an embodiment, the bucket memory manager 110 monitors the number oftimes a misallocation occurs. For example, engine 208-1 may receive arequest from client 102 for a memory size of 1 MB. Before engine 208-1accesses and has a chance to retrieve the memory request of 1 MB fromfixed size bucket 202-1 in instance 206-1, engine 208-2 accesses andretrieves the memory address in instance 206-1 that engine 208-1 plannedto retrieve. The engine 208-1 recognizes this situation as amisallocation, according to an embodiment. In response, engine 208-1initializes an allocs_missed variable to keep track of the number oftimes this situation occurs for a particular bucket and an associatedinstance 206. Each subsequent time this occurs, engine 208-1 incrementsthe contents of the allocs_missed variable by one.

In an embodiment, the bucket memory manager 110 monitors the number oftimes engine 208 allocates from global bucket 204-1 despite an availablefixed size bucket 202. For example, engine 208-1 receives a request fromclient 102 for a memory size of 3 MB. Engine 208-1 accesses fixed sizebucket 202-3 of instance 206-1, which stores pointers to 3 MB memoryblocks. However, the fixed size bucket 202-3 is empty. Engine 208-1proceeds to check each fixed size bucket 202-3 of instances 206-2 to206-N yet finds no pointers to 3 MB memory blocks. As a result, engine208-1 goes to the global bucket 204-1 of instance 206-1 for a pointer toa 3 MB memory block. If engine 208-1 recognizes the global bucket 204-1does not have a pointer to a 3 MB memory allocation, the engine 208-1allocates a 3 MB memory allocation from memory 112. At the same time,the other engines 208 are signaled by engine 208-1 to allocate 3 MBmemories from memory block 112 to fill their buckets storing pointers tothe 3 MB memory allocations. In response, engine 208-1 initializes abucket_empty variable to keep track of the number of times thissituation occurs for a particular bucket and associated instance 206.Each subsequent time this situation occurs, engine 208-1 increments thecontents of the bucket_empty variable by one.

In an embodiment, the bucket memory manager 110 monitors the totalnumber of requests for memory addresses for each instance 206. Forexample, engine 208-1 receives 100 requests from client 102 for memoryaddresses whereas engine 208-2 receives 50 memory requests. Each engine208 keeps track of the number of requests received starting after bootup in an allocs variable. The engine 208 increments the contents of theallocs variable by one every time a request is received.

In an embodiment, the bucket memory manager 110 monitors the currentnumber of buckets 202, 204 and the current number of instances 206. Thenumber of buckets 202, 204 is stored in a variable labeled numbucketsand the number of instances 206 is stored in a variable labelednuminstances. At a specific instance in time, engine 208 may acquire asnapshot of the number of buckets 202, 204 and the number of instances206 in bucket memory manager 110. The snapshot may occur periodically,such as every hour and before the system shuts down.

In an embodiment, the bucket memory manager 110 monitors the number oftimes the bucket memory manager 110 tried allocating a memory addressunder a locked condition. For example, engine 208-1 accesses fixed sizebucket 202-1. However, fixed size bucket 202-1 is locked due to engine208-2 accessing and retrieving a pointer to a memory address. The numberof retries for accessing a locked bucket 202 is stored in a variablelabeled retries. Each time the locked bucket is accessed, the contentsof the retries variable is incremented by one. Each engine 208 creates aseparate retries variable for each bucket 202 in the associated instance206.

In an embodiment, the bucket memory manager 110 monitors the number oftimes the bucket memory manager 110 failed to allocate a memory addressrequest. Specifically, the bucket memory manager 110 counts the numberof times an engine 208 returned NULL to a memory request. For example,engine 208-1 scans all of the fixed size buckets 202 and all of theglobal size buckets 204 for a pointer to a 6 MB memory allocationrequest. However, none of the buckets in the bucket memory manager 110contain a pointer to a 6 MB memory allocation nor is there enoughcontiguous memory space in memory 112 to allocate a 6 MB memory space.As a result, engine 208-1 returns a NULL to client 102. A variablelabeled failures for each engine 208 stores the number of times a NULLis returned to the client. Each time a NULL is returned by one of theengines 208, the contents of the variable labeled failures isincremented by one.

In an embodiment, the bucket memory manager 110 monitors every requestfor a memory address from client 102. For example, engine 208-1 receivesfive 4 MB address requests, six 1 MB address requests, and three 6 KBaddress requests. Engine 208-2 receives four 8 KB address requests andthree 4 MB address requests. An array labeled statarray[n] in eachengine 208 keeps track of the received address request for each of theengines 208 in a respective bucket memory manager 110. The statarray[n]stores each memory address request associated with a timestamp when anengine 208 receives the request.

In 712, the bucket memory manager 110 adjusts the bucket memory managerparameters based on the analyzing from 604 and 606. 712 expands upon thefunctionality of 608 from above. Further, the bucket memory manager 110adjusts the bucket memory manager parameters based on the set of rulesextracted from the configuration information. As mentioned above, theseset of rules define the self-tuning mode for the bucket memory manager110.

In an embodiment, one rule defines the fixed size buckets 202 with themost popular address sizes. Specifically, each of the fixed size buckets202 needs to be tuned to the workload of the client 102. For example,the statarray[n] is sampled by engine 208 for a certain amount of time,such as 5 minutes, to monitor the memory address requests. If engine 208notices a particular memory address request, such as 5 MB, is morefrequently requested from client 102 where these requests consume morethan twenty percent of the statarray[n] for a length of time, the engine208 will automatically add a 5 MB bucket 202 to instance 206. Ingeneral, for self-tuning, the bucket memory manager 110 monitors thestatarray[n] for a predetermined period. If a requested memory addressconsumes greater than a percentage threshold of the total allocations instatarray[n] during the predetermined period and a fixed size bucket 202for the requested memory allocation does not already exist, a fixed sizebucket 202 is created for the size of the requested memory allocation.In an embodiment, when a fixed size bucket 202-N is added to oneinstance 206-1 to match the current workload of client 102, the otherinstances 206-2 through 206-N also add a fixed size bucket 202-N of therequested memory address size.

In an embodiment, another rule is to avoid having too many memoryaddress sizes in an unused bucket 202. Specifically, engine 208 maycontain fixed size buckets 202 of sizes 1 MB, 3 MB, 4 MB, and 5 KB.However, if the engine 208 notices the 5 KB fixed size bucket 202 israrely used, then the engine 208 removes the 5 KB fixed size bucket 202in order to preserve memory. For example, the statarray[n] is sampled byengine 208 for a predetermined period, such as 5 minutes, to monitor thememory address requests. If engine 208 notices a memory address request,such as 5 KB, consumes less than one percent of the total allocations instatarray[n] during that predetermined period, then the engine 208 willremove the 5 KB fixed size bucket 202. Removal of the memory addressesfor the 5 KB fixed size bucket 202 consists of freeing the memoryfragments, according to an embodiment. Therefore, if a requested memoryaddress amount consumes less than a percentage threshold of the totalallocations in the statarray[n] after sampling for a predeterminedperiod, the engine 208 removes that fixed size bucket 202 from theinstances 206.

In an embodiment, another rule is to avoid and reduce any engine/bucketcontention. Specifically, a goal of the self-tuning is to pass memoryefficiently and avoid any contention between buckets. For example,engine 208-1 of instance 206-1 tries to steal memory addresses fromfixed size bucket 202-1 of instance 206-2. However, engine 208-1 ofinstance 206-2 is in the process of accessing and retrieving a memoryaddress from the fixed size bucket 202-1 of instance 206-2. Therefore,engine contention occurs and the bucket memory manager 110 degradesperformance. In order to alleviate this issue, engine 208 adds moreinstances 206. In this particular rule, the allocs_missed variable issampled for a predetermined period, such as 5 minutes, to monitor thetotal memory allocation requests and the number of times another engine208-2 stole from an engine 208-1. If the engine 208-1 notices thecontents of allocs_missed is greater than the predetermined period, suchas ten percent of the total amount of memory allocation addresses over 5minutes, then another instance 206-N is added to the bucket memorymanager 110. The added instance 206-N is populated with the same fixedsize buckets 202 as the other instances 206 and a global bucket 204.Upon adding an instance 206, an engine 208-N associated with the newlyadded instance 206-N, allocates new memory addresses from memory 112 andfills the fixed size buckets 202 and the global bucket 204 with the newmemory addresses.

In an embodiment, another rule is to avoid having too many memoryaddresses sizes in an unused instance 206. Specifically, another goal ofthe self-tuning mode is to pass memory efficiently and avoid any memorythat is not being used in an instance 206. Further, another goal of thisrule is to ensure maximum use of each instance 206. If an instance 206is not being used at all and not stealing memory address from otherinstances 206, then that instance 206 should be removed. Specifically,the allocs_missed variable is sampled for a predetermined period, suchas 5 minutes, to monitor the total memory allocation requests and thenumber of times another engine 208-2 steals from an engine 208-1. If theengine 208-1 notices the allocs_missed contents is less than apredetermined threshold, such as 0.1 percent of the total amount ofmemory allocations, then that particular instance 206, is removed fromthe bucket memory manager 110.

Because of each of these rules, there are variations to actions that maybe performed. Specifically, a fixed size bucket 202 may be created orremoved and an instance 206 may be created or removed. Further,additional addresses may be added or removed from the fixed size bucket202 or global bucket 204 if the bucket is greater than the max fillthreshold or does not have any addresses in the bucket. In anembodiment, each engine 208 may perform these actions in parallel withactions from the other engines 208.

In 714, the engine 208 acts on the request from client 102 and passesthe requested memory address to the client 102. 714 expands upon thefunctionality of 608 from above. As mentioned in 516, the engine 208passes a pointer of the requested memory address from the fixed sizebucket 202-1 or the global bucket 204 to the client 102.

This process loops at 706 to monitor the bucket memory manager 110 uponreceiving a request from client 102 for a requested memory address,according to an embodiment. In an alternative embodiment, the bucketmemory manager 110 continuously monitors the self-tuning bucket memorymanager parameters even when no requests are received for memoryallocation from client 102.

FIG. 8 is a block diagram of a self-tuning environment 800, according toan embodiment. In addition or alternatively to the description of theoperations of the self-tuning mechanism within the bucket memory manager110 with respect to FIGS. 6 and 7, FIG. 8 illustrates a self-tuningmechanism 802 operating with one or more processing application(s) 804.In some embodiments, self-tuning mechanism 802 begins operating withprocessing application 804 upon boot up of the DBMS 104, or at some timethereafter. Specifically, the self-tuning mechanism 802 may be compiledor linked with the processing application 804 upon a client 102 invokingthe processing application 804. The processing application 804 may beany application associated with a processor or one or more engines orcomputing modules. For example, the processing application 804 may bethe bucket memory manager 110, a web browser, a media player, a computergame, to name a few examples, or any combination thereof. Theself-tuning mechanism 802 may be included with and/or operate with theprocessing application 804 to improve efficiency and processing timesassociated with the processing application 804.

In an embodiment, the self-tuning mechanism 802 in the environment 800follows a similar rule structure as the self-tuning mechanism describedin method 700 with regard to the bucket memory manager 110. In anembodiment, however, the rule structure of the self-tuning mechanism 802is defined following the compilation of the processing application 804with the self-tuning mechanism 802. In an embodiment, followingcompilation, the rule structure is set based on configurationinformation in a configuration file associated with the processingapplication 804. For example, if the processing application 804 is acentral processing unit (CPU) that is processing items off a queue, theparameters defined in the configuration file may set the number anddepth of the queues; the amount of time items are allowed to remain onthe queue before removal; and/or, a max threshold amount of items in anyqueue. In an embodiment, the self-tuning mechanism 802 utilizes the sameor similar rule structure described in method 700 for the processingapplication 804 based on this configuration information. For example,similar to as described in 712, the bucket memory manager parameters areadjusted based on the analyzing in 604 and 606. Similarly, theself-tuning mechanism 802 may adjust the parameters for the CPUprocessing items off a queue example based on similarly defined rules.The same or similar functionality can be applied for any self-tuningmechanism 802 with any associated processing application(s) 804.

Various embodiments can be implemented, for example, using one or morecomputer systems, such as computer system 900 shown in FIG. 9. Computersystem 900 can be used, for example, to implement method 500 of FIG. 5,method 600 of FIG. 6, and method 700 of FIG. 7. For example, computersystem 900 can retrieve a memory allocation based on a request fromclient 102 using buckets in a bucket memory manager 110. Computer system900 can further self-tune a plurality of bucket memory managerparameters based on a current workload of memory allocation requestsfrom client 102, according to some embodiments. Computer system 900 canbe any computer capable of performing the functions described herein.

Computer system 900 can be any well-known computer capable of performingthe functions described herein.

Computer system 900 includes one or more processors (also called centralprocessing units, or CPUs), such as a processor 904. Processor 904 isconnected to a communication infrastructure or bus 906.

One or more processors 904 may each be a graphics processing unit (GPU).In an embodiment, a GPU is a processor that is a specialized electroniccircuit designed to process mathematically intensive applications. TheGPU may have a parallel structure that is efficient for parallelprocessing of large blocks of data, such as mathematically intensivedata common to computer graphics applications, images, videos, etc.

Computer system 900 also includes user input/output device(s) 903, suchas monitors, keyboards, pointing devices, etc., that communicate withcommunication infrastructure 906 through user input/output interface(s)902.

Computer system 900 also includes a main or primary memory 908, such asrandom access memory (RAM). Main memory 908 may include one or morelevels of cache. Main memory 908 has stored therein control logic (i.e.,computer software) and/or data.

Computer system 900 may also include one or more secondary storagedevices or memory 910. Secondary memory 910 may include, for example, ahard disk drive 912 and/or a removable storage device or drive 914.Removable storage drive 914 may be a floppy disk drive, a magnetic tapedrive, a compact disk drive, an optical storage device, tape backupdevice, and/or any other storage device/drive.

Removable storage drive 914 may interact with a removable storage unit918. Removable storage unit 918 includes a computer usable or readablestorage device having stored thereon computer software (control logic)and/or data. Removable storage unit 918 may be a floppy disk, magnetictape, compact disk, DVD, optical storage disk, and/or any other computerdata storage device. Removable storage drive 914 reads from and/orwrites to removable storage unit 918 in a well-known manner.

According to an exemplary embodiment, secondary memory 910 may includeother means, instrumentalities or other approaches for allowing computerprograms and/or other instructions and/or data to be accessed bycomputer system 900. Such means, instrumentalities or other approachesmay include, for example, a removable storage unit 922 and an interface920. Examples of the removable storage unit 922 and the interface 920may include a program cartridge and cartridge interface (such as thatfound in video game devices), a removable memory chip (such as an EPROMor PROM) and associated socket, a memory stick and USB port, a memorycard and associated memory card slot, and/or any other removable storageunit and associated interface.

Computer system 900 may further include a communication or networkinterface 924. Communication interface 924 enables computer system 900to communicate and interact with any combination of remote devices,remote networks, remote entities, etc. (individually and collectivelyreferenced by reference number 928). For example, communicationinterface 924 may allow computer system 900 to communicate with remotedevices 928 over communications path 926, which may be wired and/orwireless, and which may include any combination of LANs, WANs, theInternet, etc. Control logic and/or data may be transmitted to and fromcomputer system 900 via communication path 926.

In an embodiment, a tangible apparatus or article of manufacturecomprising a tangible computer useable or readable medium having controllogic (software) stored thereon is also referred to herein as a computerprogram product or program storage device. This includes, but is notlimited to, computer system 900, main memory 908, secondary memory 910,and removable storage units 918 and 922, as well as tangible articles ofmanufacture embodying any combination of the foregoing. Such controllogic, when executed by one or more data processing devices (such ascomputer system 900), causes such data processing devices to operate asdescribed herein.

Based on the teachings contained in this disclosure, it will be apparentto persons skilled in the relevant art(s) how to make and useembodiments of the invention using data processing devices, computersystems and/or computer architectures other than that shown in FIG. 9.In particular, embodiments may operate with software, hardware, and/oroperating system implementations other than those described herein.

It is to be appreciated that the Detailed Description section, and notthe Summary and Abstract sections (if any), is intended to be used tointerpret the claims. The Summary and Abstract sections (if any) may setforth one or more but not all exemplary embodiments of the invention ascontemplated by the inventor(s), and thus, are not intended to limit theinvention or the appended claims in any way.

While the invention has been described herein with reference toexemplary embodiments for exemplary fields and applications, it shouldbe understood that the invention is not limited thereto. Otherembodiments and modifications thereto are possible, and are within thescope and spirit of the invention. For example, and without limiting thegenerality of this paragraph, embodiments are not limited to thesoftware, hardware, firmware, and/or entities illustrated in the figuresand/or described herein. Further, embodiments (whether or not explicitlydescribed herein) have significant utility to fields and applicationsbeyond the examples described herein.

Embodiments have been described herein with the aid of functionalbuilding blocks illustrating the implementation of specified functionsand relationships thereof. The boundaries of these functional buildingblocks have been arbitrarily defined herein for the convenience of thedescription. Alternate boundaries can be defined as long as thespecified functions and relationships (or equivalents thereof) areappropriately performed. Also, alternative embodiments may performfunctional blocks, steps, operations, methods, etc. using orderingsdifferent than those described herein.

References herein to “one embodiment,” “an embodiment,” “an exampleembodiment,” or similar phrases, indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it would be within the knowledge of persons skilled in therelevant art(s) to incorporate such feature, structure, orcharacteristic into other embodiments whether or not explicitlymentioned or described herein.

The breadth and scope of the invention should not be limited by any ofthe above-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. A computer implemented method for self-tuning abucket memory manager, comprising: receiving, by at least one processor,requests for memory blocks of varying memory sizes from a client;determining, by the at least one processor, a workload for the clientbased on the requests; analyzing, by the at least one processor, aplurality of buckets in the bucket memory manager based on the workloadto determine that usage of a first bucket of the plurality of bucketsfalls below a usage threshold; and deallocating, by the at least oneprocessor, the first bucket in response to the analyzing; wherein atleast one of the receiving, determining, analyzing, and deallocating areperformed by one or more computers.
 2. The method of claim 1, whereinthe plurality of buckets comprise fixed size buckets and a global bucketfor non-fixed size memory addresses.
 3. The method of claim 1, thedetermining further comprising: determining a request frequency for aparticular memory size from the requests.
 4. The method of claim 1, theanalyzing further comprising: determining a match between a bucket sizeassociated with a second bucket of the plurality of buckets and a memorysize from one of the requests.
 5. The method of claim 1, furthercomprising: adding memory addresses to a second bucket of the pluralityof buckets when the second bucket is empty; and adding the second bucketto an instance based on the analyzing.
 6. The method of claim 1, furthercomprising: communicating via an engine with a first instance and aplurality of other instances to distribute memory addresses to theplurality of buckets and to retrieve the memory addresses from theplurality of buckets.
 7. The method of claim 6, further comprising:locking via the engine a second bucket of the plurality of buckets whiledistributing and retrieving a memory address from the second bucket. 8.A system, comprising: a memory; and at least one processor coupled tothe memory and configured to: receive requests for memory blocks ofvarying memory sizes from a client; determine a workload for the clientbased on the requests; analyze a plurality of buckets in a bucket memorymanager based on the workload to determine that usage of a first bucketof the plurality of buckets falls below a usage threshold; anddeallocate the first bucket in response to the analyzing.
 9. The systemof claim 8, wherein the plurality of buckets comprise fixed size bucketsand a global bucket for non-fixed size memory addresses.
 10. The systemof claim 8, the at least one processor further configured to: determinea request frequency for a particular memory size from the requests. 11.The system of claim 8, the at least one processor further configured to:determine a match between a bucket size associated with a second bucketof the plurality of buckets and a memory size from one of the requests.12. The system of claim 8, the at least one processor further configuredto: add memory addresses to a second bucket of the plurality of bucketswhen the second bucket is empty; and add the second bucket to aninstance based on the analyzing.
 13. The system of claim 8, the at leastone processor further configured to: communicate via an engine with afirst instance and a plurality of other instances to distribute memoryaddresses to the plurality of buckets and to retrieve the memoryaddresses from the plurality of buckets.
 14. The system of claim 13, theat least one processor further configured to: lock via the engine asecond bucket of the plurality of buckets while distributing andretrieving a memory address from the second bucket.
 15. A tangiblecomputer-readable device having instructions stored thereon that, whenexecuted by at least one computing device, causes the at least onecomputing device to perform operations comprising: receiving requestsfor memory blocks of varying memory sizes from a client; determining aworkload for the client based on the requests; analyzing a plurality ofbuckets in a bucket memory manager based on the workload to determinethat usage of a first bucket of the plurality of buckets falls below ausage threshold; and deallocating the first bucket in response to theanalyzing.
 16. The computer-readable device of claim 15, the determiningfurther comprising: determining a request frequency for a particularmemory size from the requests.
 17. The computer-readable device of claim15, the analyzing further comprising: determining a match between abucket size associated with a second bucket of the plurality of bucketsand a memory size from one of the requests.
 18. The computer-readabledevice of claim 15, the operations further comprising: adding memoryaddresses to a second bucket of the plurality of buckets when the secondbucket is empty; and adding the second bucket to an instance based onthe analyzing.
 19. The computer-readable device of claim 15, theoperations further comprising: communicating via an engine with a firstinstance and a plurality of other instances to distribute memoryaddresses to the plurality of buckets and to retrieve the memoryaddresses from the plurality of buckets.
 20. The computer-readabledevice of claim 19, the operations further comprising: locking via theengine a second bucket of the plurality of buckets while distributingand retrieving a memory address from the second bucket.